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low compression problem. help!!

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Old Aug 18, 2005 | 09:07 PM
  #1  
305Camaro84's Avatar
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Joined: Oct 2004
Posts: 53
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From: Center Valley PA
Car: 1894 Camaro Berlinetta 305 auto
Engine: 305 LG4
Transmission: TH 700 R4
low compression problem. help!!

sorry this is a bit lengthly i just wanted to be sure i was therough.
i ran a compression test after my car was runnin really bad (really really bad) and here are the results

1: 77
2: 77
3: 76
4: 75
5: 76
6: 77
7: if i would of got the thing in the spark plug hole i wouldnt have a right hand
8: 75
now i dont know what the problem is i was thinking timing and correct me if im wrong but i think it may have jumped time. would these results look like a timing issue im already down to the harmonic ballancer so i might pull out the cam and put a new one in but now for my other problem
the harmonic ballancer... i got the crank pully off with the puller but when i try to get the harmonic ballancer off the puller just spins the bolt in the center of the harmonic ballancer and is starting to bend it after two attempts at pulling it. if anyone has an idea of how to get it off without a puller or some way to use the puller so it doesnt bent that bolt. thanks
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Old Aug 19, 2005 | 06:06 AM
  #2  
Damon's Avatar
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Joined: Sep 1999
Posts: 7,072
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From: Philly, PA
I was going to ask if you had blocked the throttle wide open when you did the testing but that would only knock off maybe 10-20 PSI. You're WAY WAY off the mark. I'd guess your timing chain has slipped a tooth or two, causing the intake valve to close VERY late and drop your cranking compression way down. Fortunately the readings are EVEN, so you probably haven't bent any valves or done any other mechanical damage yet.

I'm assuming the internals of the engine are "stock" right now- no big aftermarket cam, cylinder head swap or anything like that.

To remove the balancer you need to take the big center bolt out that retains the balancer to the crank first. I'm assuming you did that since it also retains the crank pulley. Forgive me, but I had to point that out.

The removal tool is SUPPOSED to have the center bolt turn. You need to put the pointy ended attachement on the end of the big center bolt- it centers it up on the chamfered threads in the snout of the crank so it won't slip off sideways and gives it a sloid surface to push against. The 3 perimeter bolts out on the wings hold the balancer to the body of the tool (make sure they're adjusted evenly). Then you turn the big center bolt, it pushes in on the snout of the crank and pulls out of the balancer via the 3 bolts, removing the balancer.

Last edited by Damon; Aug 19, 2005 at 06:13 AM.
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Old Aug 26, 2005 | 08:36 PM
  #3  
305Camaro84's Avatar
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Junior Member
 
Joined: Oct 2004
Posts: 53
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From: Center Valley PA
Car: 1894 Camaro Berlinetta 305 auto
Engine: 305 LG4
Transmission: TH 700 R4
thanks

thanks i got the harmonic ballancer off by putting the flat tip in the bold hole (making sure that the thing didnt touch the threads) it pulled it off great. i kinda ruined my dad's pointy tip, it kinda just ground down to almost flat so. but it did jump time, quite a bit i might add... almost 180 degreese. piston one was at tdc and the dots were almost on complete oposite sides of the sprockets thanks for the help
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Old Aug 29, 2005 | 11:04 AM
  #4  
Damon's Avatar
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Joined: Sep 1999
Posts: 7,072
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From: Philly, PA
Yep, that'll do it. You're on your way. Fresh timing chain, line up the dots and you'll be good to go.

BTW- there are 2 ways the dots on the timing chain gears can line up when #1 is at TDC. They can either end up both at the 12 o'clock position pointing straight up (#1 at TDC of compression stroke) or lined up "dot to dot" with the cam gear pointing straight down (#1 at TDC of exhaust stroke). So it's not like having the dots being 180* apart is necessarily a bad thing. It's only if they are ALMOST 180* apart!! That's when you've slipped a tooth or two!

Last edited by Damon; Aug 29, 2005 at 11:07 AM.
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